In acid soils you can select the crops that can growth in this contitions(pH 6.0 - 6.5 is slightly acidic, and you can find cultures that can be cropped under this conditions). If soil is acid to  highly acidic , in some areas of Northern Spain the use to increase the pH by liming the soil in a gradual / gentle way. You can find different product for liming fron rocks, wastes (from marble industries; animal bones; etc) 

I agree with Rocío Millán that the easiest solution would be to find a cropping solution that works best with the soil types in the area. Unfortunately, a blanket prescription cannot be given because soil properties will be different for different areas. Without knowing how the soil will react you cannot say what treatment will work best for adjusting the pH of the soil

you can go for liming 

I would suggest liming to increase soil pH in time and use of microbiological products that contain MOs that 'work' in acid soil.

Along with lime to quickly but not not permanently or reliably,increas Ph try the addition of compost. While nominally a soil acidifier. Compost is much more long lasting  and stable as a soil amendment. In my experience (a Ph of 6.5 is optimal for nutrient uptake, Especially trace minerals,. 

Also the planting of a pea or bean cover crop, (green manure) should aid in nitrogen replenishment and allow for higher yields. 

By using liming, and compost. Both materials are increase the pH of the soil

Please, take into accoutn that pH must be increased little by little, no more than 0.5- .1 (maximun) per year, by liming, due to if you added a hugh amount of calcium carbonate based soil amendment, you can form "crust" adn precipitates and at the end this amendment doesn´t work. You can use: marble sludges (a waste from marble industry); limestones; calcium carbonates; rest of marine shells or animal bones; residues from beet and sugar industries, ....  if you want to have a added value by the reuse and valorization of some wastes. The combined use with compost or the organic fraction of urban waste or farmland, etc...can mprove the soil quality. (pay attention on the kind and origin of the residues before to be applied in soils!!!). Regards. Rocio 

The solution is only apparently easy to be managed, of course some species like blueberry can take advantage by acid soils, on the other hand for many others conditions, careful liming and compost of high quality may improve soil performnances 

 Dear colleagues, we getting interesting  and practical solutions for management of acid soils.As mentioned by Professor Scalabrelli some plant species may be adopted to acidic environment like blueberry.We need crop species and  varieties adoptable to low pH

Dear Doctors I would like to make a pitch for complete soil analysis and resolving the issues with micronutrients. Many of the acid soils have multiple micro nutrient deficiencies. If we lime an acid soil it is likely to become micronutrient deficient unless the micronutrients are in the soil. Liming infrastructure is also not always available.  Although 1 to 2 ppm Boron would optimize our soil in acid conditions they rarely have that quantity. An exciting area of investigation is work showing the counteracting capacity of Boron in relation to Aluminum toxicity. The supplementation of micronutrients does not require huge quantities but can have major effects. It is particularly important for legumes that respond to Cobalt, Molybdenum and Zinc which can be provided by seed treatment. Micronutrients can also be applied to compost to help ensure no toxicity issues.  For you who want to check out any prevalence of Boron deficiency look to papaya fruit that show bumps.  Any looking at thousands of soil analysis I rarely see the boron in 1 to 2 ppm range recommended and the majority of times it is well under 1 ppm.

Dr.Hepperly,you have raised an important issue  of micronutrients in acid soils especially B,Mo.Co,Zn etc.We normally follow a critical limit of  0.6 mg B/kg soil (0.6 ppm) hot water soluble B and apply 1 kg/ha B as Borax ( foliar application).I think it needs to be investigated, the role of B in Al toxicity conditions and its higher requirement in soil.Of course the compost is a better medium to fortify with micronutrients and it may definitely help in acid soils.Co  requirement in legumes in acid soils is also important.Another important suggestion is seed treatment  with Zn and Mo.Can sufficient Zn be loaded on seeds to meet its requirement(in all field crops)?

AndMo

A. Subba Rao,

Astute observations as always.

I believe the use of fine volcanic dust as an amendment in compost is very much worth while because it will ensure that micronutrient issues are resolved. I particularly like it in the use of compost for starting plants.

I also think that the micronutrient seed treatment is extremely economical and environmental safe as well as applicable if the materials are available. As you know Molybdenum is a very very interesting case as it is an essential co factor for Biological Nitrogen Fixation key to sustainable farming systems and it more available in Alkaline conditions making it some what of a strange bird. I do not think many people assay this either in the soil or in plants I would like your take on that.

To this day the power of materials that are powerful in micro quantities is astounding reminds of how nano technologies work based and their smallness.

I  live in an akline region. (Soil Ph 7.5 to 8) So I have a different problem, but for those of you in more standard acid reigrons I would recommend composting heavily (3-4 inches in the spring.) 

In alkaline region your first pH goal should by 7.3 where a lot of deficiency are no longer critical. Try using elemental Sulfur in your compost pile I think a cup of this per cubic meter in the composting would drive the final pH near neutral. If you are conventional the use of ammonium sulfate will also drive pH to where micronutrients will no longer be an issue as they commonly are in alkaline areas. For alkaline regions do not apply any liming material if you have a Calcium deficiency use gypsum which does not elevate the alkaline condition but can provide needed Calcium your Calcium level can be assayed in the plant to confirm if you have any real need.

Many composts can be alkaline and can in some cases result in micronutrient chlorosis.

In relation to this you plant by seed petunias and their terminals are chlorotic with green veins and yellow interveinal it is a good biological indicator of iron chlorosis indicating your pH may be 7.3 or beyond where these problems occur.

In temperate climates the great organic acidifier is peat moss which has a pH of about 4.0. It can used with acid loving plants like blueberries but also can be employed to adjust you mixture say with alkaline soil and compost down to slight acidity 6.0 to 6.7 which is most favorable for most plant species.

For those of you in alkaline soil areas it might be useful to find materials with the potentials of peat moss in your areas.

Paul:

Thanks for your input. We have about 30 acres of gardens an Gateway. We compost regularly. I will recommend mixing ammonia sulfate with the pile (generally about 300 yards)  and we will see if it helps.

I will report back in the summer f it help's

Dear Dr.Hepperly,your suggestions for enriching  nutrients or for adjusting pH are interesting.Addition of any one of  elemental sulphur,gypsum,pyrite and ammonium sulphate(we tested  S and pyrite ) depending on availability is O.K.Regarding volcanic ash I have some reservation.Once we analysed a few samples of volcanic ash and we find no much higher nutrient concentrations in volcanic ash compared to our normal soil total analysis .Do you have some data on volcanic ash?

Dear colleagues, along with micronutrients  nutrition problem ,we have to deal with the problem of toxicity of Al, Fe and Mn in different acid  soils depending on soil environment and see how to tackle them through management or other options. I request your valuable inputs on this aspect.

Dear Doctor Rao,

When I was teaching farmers in Australia Soil Care and Tafe. I collaborated with David Forrest a Professor and Farmer in New South Whales.

Australia is the oldest continent very notable for many micronutrient deficiencies. I found them using volcanic rock as part of the compost mix with good effect. My feeling if it works kudos and try it in other areas if it does work there try again and take looks at alternatives.

here is some context of my enthusiasm.

In the areas of Naples Italy the volcanic region is highly productive compared to other regions.

The famous Kona Hawaii premium coffee is dependent on volcanic soil and as well the fame of Colombian and Costa Rican mountain grown.

Of particular interest to me has been extraordinary soil organic matter associated with andisols and its association with allophane.  Andisol are extraordinary of Nitrogen and Phosphorus contents.

At Mount St. Helens the comparison of   Ash to Soil was: 178 to 3 ppm P, Sulfate 53 to 3, Zinc 28 to 4 Copper 6 to 1 and Potassium 260 to 140. that is suggestive to me.   The experience in Iceland also shows a definite enrichment factor related to the ashes. Also farmer testimonies. In central America they are big proponents of the value of volcanic materials.

I do not think composting is an exact science but believe the mixture of inputs is a very good strategy for covering the bases. In relation to volcanic material its richness is related to its newness but much of our fertility issues are related to lose of micronutrients oldness and leaching. Liming tends to exacerbate micronutrients issues but I see potential in the volcanic rock idea. Especially when  we research it more thoroughly but the idea and experience makes sense but needs local experience to become most fruitful.

Ashes are also initially quite rich in Silica. It worth looking at with more in detail. Composting remains an area where art and science are involved.

The most successful composter I know all swear that diverse materials make better compost and if you ask why I would suggest it better covers the nutritional bases but I cannot precise it.

Dr.Hepperly,thank  you very much for providing incites to volcanic ash and volcanic soil areas. I understand the diversity,variety and art in composting.I shall continue to learn more.

Dear Rao, I am glad to hear your question according to my expertise. Even I haven't did work during my PhD, but my friends/labmates did this types of work. And involve in same group during field and lab study. So if you interested to work using biochar technology. I suggest you to observe under lab condition first and see the bonding capability of Fe and Al with biochar and measure the soil pH. 

1. Soil ph 5.5 to 6.5 you need at least 5-10% rice husk biochar 

You can conduct a moro experiment under lab condition and incubate the soil for 40 days at least with 20% moisture conditions. Open the soil in mid and remix again and incubate for remaining time. and measure the properties.

Biochar may offer one the opportunities ,if it has reasonably high CEC which needs to be shown in diverse biochars.

Dear Rao, let you try under laboratory conditions as I suggest you, I hope you will get fruitful results in compression of other treatments. I do not know either India is producing Biochar via pyrolyses technology or not. But you can produce at small scale for experimental purpose and utilize.

With best wishes. 

The effects of biochars can be related to their enormous specific surface area. These are envisioned as micro habitats for beneficial microbes including success with mycorrhzal fungi.

The book Biochar for Environmental Science and Technology edited by Lehman and Joseph is a tour de force of the conceptual and application frameworks.

I guess the application of high temperature crop residue biochar can be a viable option for acidic soil reclamation and crop productivity improvement.

If needed, it can be applied with compost or some other organic manure to further improve the productivity and neutralize soil acidity because such soils must have some P limitations.

One of the best ideas is to include biochar as an amendment in manure supplemented compost. The Amazonia Black Soils were products of return of ashes with human and animal and plant wastes as such they constituted a varied and completed compost diet.

Compost of Lantana camara different parts and P.hyterophorus will very useful in such land because both have are allelopathic and freely available.

Article Allelopathic properties of Lantana camara

Interesting discussion on biochar use in acid soils for improving their productivity.The positive attributes which will benefit acid soils appear to be  high CEC,high surface area and high pH of biochars. As per current understanding Low temperature produced biochars  contribute to increase in soil CEC (after sufficient time for interaction between soil and biocha) and  possibly help to bind /complex the heavy metals in acid soils .Biochars  produced from animal biomass or manure tend to have higher  pH than biochars from plant species.So one has choose right biochar and right amount also(the change in pH should not negatively affect the nutrient availability).One basic point is if the biochar has high surface area(providing microhabitate to microbes),high CEC  and high water holding capacity (and behave like humus in soil),how long the biochar remains in soil(with out decomposition) and contribute to environmental cause,i.e mitigation of climate change by storing carbon for  centuries in soil?Please go through the following  review paper.The biochar dilemma. A. Mukhergee and R.Lal Soil Research ,2014,52,217-230.

Use of lime as nutrient for Ca supplementation than amendment is one option and giving good results. For example, 500 kg lime per hectare per crop in furrow application. Application of F Y M in good amount also acting like an amendment in moderately acidic soils.

When you have an Aluminum toxicity liming to 5.3 pH will control it. 

 if you have Manganese toxicity you should lime to 5.7 this would be common if you are in an oxisol an you have manganese nodules present in your soil.

If you want to provide Calcium but have a slightly acid or neutral pH but lack sufficient Calcium use gypsum as a Calcium source. Do not lime if your soil is  near neutral or certainly if it is alkaline. Liming in that condition will cause seriouse and unnecessary micronutrient deficiency.

 Many acid soils are Magnesium deficient if you have a Magnesium score of under 100 in your soil test you should use dolomitic limestone to adjust pH as it will also provide Magnesium which is deficient in your soil. 

If not, use Calcitic lime it is cheaper.  

Look also the see if your Sulfur content is sufficient.

Beside the effect of Calcium in remediating Aluminum toxicity there is increasing information that Boron will remediate Aluminum toxicity and it may serve for the mobilizing of Calcium in you acid soil condition. This is most cost effective potentially because the rates are very low.

 For Boron in the soil to be sufficient soil test should fall in 1 to 2 ppm. In the plant analysis sensitive crops should have more than 25 ppm in the foliar. Boron deficiency is found as bumpy fruit in papaya and pear and hollow heart in cabbage and alfalfa and as tip die back in coffee and banana. Witches broom is the result of  apical dominance the lateral buds give a witches broom symptom.

Epidemiology studies are showing that Boron in humans is related to bone problems arthritis is greatly increased when intake is less that 1 mg per day and greatly reduced if over 3 mg per day. Boron in humans is not toxic and you may want to consider taking some if you are from an area with Boron poor soils and family members have shown arthritis history.

I have an acidity and liming Power Point for anyone interested connect at [email protected] if you desire me to send it to you if it is not to long in memory for your service.

In relation to biochar it is important to do your rate study as usually the studies are at unnecessary high rates to demonstrate an effect without demonstrating the dose response.

I agree with Dr. Paul R. Hepperty.. It is very common practice to use over-rates of biochar in studies without any regard to it unwanted effects on crops, soils (acid soils), nutrient availability, particularly when commercializing this approach will that much quantity of biochar would be available to farmers.

In relation to acid soil condition Boron deficiency is quite common in sandy acid soil low in Boron. Under the same conditions Aluminum toxicity and others are present. The liming to 5.3 pH for Aluminum and 5.7 for Manganese can be sufficient to eliminate toxicities.

In the case of acid soils they are often bereft of adequate Magnesium and in that case dolomitic limestone should be employed.

Some information has been accumulating that Boron a light element can facilitate the movement of Calcium and Magnesium and remedy Aluminum toxicity. Since Boron is employed in such small amounts the study of field application of boron for acid soil infertility seems a fruitful research venue and an area for application. It may be more immediate and cost effective before a stabilized liming practice can develop.

In areas of low soil Boron and in areas of low dietary Boron arthritis has been shown to be elevated. For areas with micronutrient deficiency the use of trace mineral blocks can be quite effective with the animals working as spreaders. An additional opportunity is to target micronutrients into the compost and have them in organic forms for application in the targeted use of compost.

the best way is to apply lime during the off season before planting, to provide a good space for chemical reactions to take place. Avoid applying lime then plant immediately, because some chemical reactions requires time.therefore  add organic fertilizers to soil as to improve the microbial activities and soil structure

The deep incorporation of lime is recommended particularly when the subsoil is acid. The deeper the lime is incorporated the better texture conditioned by Calcium effect on aggregation and the decreased subsoil toxicity and deficiency results in deeper root crops.

Since the tradtional German moldboard plow can be quite destructive it has fallen out of favor and its plow shoe compacts soils un necessarily

. I would recommend a disc plow for deep liming if you find one and once limed go back to no tillage or reduced till.  If you are in old tropical weathered soils ultisol and definitely oxisol the lime moving downward better than in many of temperate soils.  In case of green manure we let it decompose 3 to 4 weeks and the reaction of lime will depend on its fineness but may require 5 to 6 weeks I think.

If you compost your manures and add lime and phosphate it will be useful for your condition. 

Dr.Hepperly,several good points have emerged from your comments and also other participants on management of acid soils.Liming up to 6.0 pH will take care of Al and Mn toxicity problems.As Dr. Singh has pointed out, in India we are now advocating application of small rates ,500 kg/ha furrow application of lime and manure .We are also promoting the use of byproduct lime sources like paper mill sludge.Dolomite lime can be preferred where ever it is possible to get and also when Mg deficiency is known in that area.We shall encourage our young scientists to take up work on B /Al interaction in acid soils and the possible benefit B application on Al toxicity.

Dear Doctor Rao

Dolomite is only needed from my personal experience when Magnesium tests out less than 100.

In some cases as in Latin American subsoil acidity is critical.

The Kaolinitic soils have ability to leach down lime but that movement is difficult for Mortmorrilonite soils and deep application would be preferred.

Doctor I really appreciate your leadership in these areas it is very inspiring.

Kudos to you.

Dr.Thank you very much for your prompt reply/response.On Mg we have limited work and need to generate more information. We also need to determine our own critical limits of Mg for our soils as CEC of soil and base saturation with respect to Ca and K are important in deciding the Mg needs.The extent of subsoil acidity problem in acid soils of India is also not known to me.This also needs to be worked out from the existing database or  fresh attempt has to be made.Under Indian conditions soil acidity is not a problem in montmorrilonite dominant soils except in some pockets in West Bengal state.Thank you very much for very encouraging words.

You might be interested in the results of this study

Reeve etal Bioresource Technology 101 (2010) 5658–5666

Pfeiffer field spray (a biodynamic spray) was nearly as effective as liming for mild acid soil remediation.

Limestone incorporate to a layer of 20 cm of soil. You can also use agricultural gypsum to carry base in depth. The liming should be done unless 2 months before the planting.

Thank you Drs Lia and Avelars for your comments.I have no experience with biodynamic  spary.I welcome comments of colleagues who have worked in  this line.We note the suggestion of  Dr.Avelar.I had opportunity to see a very good document on rice in North East India in Rice Knowledge Management Portal.In India acidic soils 1.25%),high organic matter(>2.98%),shallow water table(

Dear Doctor Rao

Thank you for the background information on iron toxicity in North eastern India especially on submerged rice. My experience with Manganese and Aluminum acid soil toxicities suggest that seedling stages are particularly susceptible and the plant coping ability increases after the sensitive seedling stage.  I would think this might occur also with your iron issue. With that said and thinking economics 2 strategies might be considered. First concentrate on tolerance and varietal resistance combined with seed treatments to reduce the seedling toxicity. The type of fertilization which would have some antagonism is Phosphorus based triple super phosphate as starter  should have an antagonism with solubilized Iron. Secondly because Zinc and Copper could be deficient their application is warranted and they are antagonist along with P to iron translocation.  It appears that potassium has some value in mitigation and might be employed was a potassium nitrate which would contribute to high root pH in the early growth stages.  Because ammoniated urea would contribute to increased acidification the use of nitrate with potassium may be very warranted under your conditions. Finally the use of localized seed band liming would bring the establishment which may reduce toxicity in the critical seedling stages. Some times we have big problems and only a tool kit with small effects if these little hammers are used together however they can often address the big issues using only small hammers.  

Dr.Hepperly very good and very pertinent suggestions which can be considered for implementation and also initiating some research work on the lines suggested.Breeding rice varieties tolerant to high iron  in soil is important.Seed treatment ,exploiting the ion antagonism for advantage,application of phosphate, potassium etc as suggested ,band placement of lime(upland rice)or at critical stages in lowland rice etc need urgent attention.

Lime induced CO2 production is claimed to increase green house gas in atmosphere. So alternative to lime like flyash may be used. In addition, few adaptive management strategies may be use for sustainable management of acid soils